Surge irrigation systems in general by the surge irrigation control valves, automatic controllers, water pipelines and other equipment, including control valves and the entire system since the controller is the core equipment. The current surge in foreign countries have irrigation control valve market. In recent years China has imported several sets of surge irrigation equipment, as a result of the high cost, only for a limited number of pilot studies. Taking into account the water-saving irrigation and irrigation automation is an inevitable trend of future development, the development of conditions suitable for surge irrigation equipment is very necessary. Conjunction with national "Ninth Five-Year Plan" scientific and technological project, after several years of efforts, has developed a surge irrigation control valves and automatic controllers, the preliminary results achieved.
1 surge irrigation equipment components
1.1 Surge irrigation control valve
Automated irrigation, taking into account the needs of irrigated areas, the development of surge irrigation control valve structure using two-way switch to switch the direction of water flow to promote, in accordance with instructions from the controller to achieve the intermittent water supply to control the process. Especially in unattended mode, after the end of irrigation can be automatically cut off the water quickly to avoid waste caused by excessive irrigation. Control valve materials currently made from iron, the main component elements include: valve, valves and slow down box.
Body structure similar to three, from three diameter 200 mm (8 ") combination of iron pipe linking one end and water connected to the outlet at both ends. Valve gasket for sealing a periphery of the circular gate, in which upper and lower ends of the central axis by the bearing seal with the body and slow down box to connect. by Gearbox control gates at right angles around the central axis for rotation, to achieve the current state of open and closed. Gearbox closed valve was fixed in on both sides and through the central axis of phase with the gate. box with: (1) transmission, taking into account the work of worm drive with a smooth noise-free, etc. can be self-locking, the design of the ordinary cylindrical worm and worm gear reducer drive; (2 ) drive, the gate valve used to control micro DC motor; (3) Locator by light control and light control panels, designed to determine the status of the valve gate; (4) reducer, high-speed operation motor (3 000 r / min) speed reducer through the levels to 10 r / min or so, and then drives the valve; (5) buffer to prevent motor overload and ensure the valve closed state.
1.2 Automatic Control
Since the surge controller is the control center of the irrigation system, control circuit board and software is the core of the controller, it accepts manual input of parameters, surge valve operating instructions issued to achieve the turn of the gate headstock. Location by the photocell gate position controller phototube signal received before deciding whether to hoist motor. Since the main controller of the following parts.
Control part. 89C518-bit microcontroller used as the core, with the composition of the keyboard and display. Keyboard used to set the system time, starting time for each irrigation time, intermittent time and frequency surge. These input parameters are automatically saved, power down or power-down is not lost. 6 LED display by the digital control of the display parameters and the working hours of state, due to the lower-power scanning. System clock for the 24 h system, the use of back-up batteries, shut down after the clock is still working correctly.
Part of motor control. 74LS07 driven by 4 relays, push the motor left and right rotation gate. When not working at both ends of the electrical grounding. When the motor is to the left termination +6 V, the right end of the ground, inverted, then left grounded, then the right end of the +6 V.
Part of the location of sensor. From 4 optocoupler, namely the two gates of the switching instructions, and will return control to receive part of the signal.
Power part. By the solar panels, 4 Ah / 6 V battery and power supply reverse anti-LDO regulator LM2940 device components. Solar panels normally float on the battery. Surge irrigation system, the batteries provide power for equipment and supplies through the main board after the LM2940 voltage regulator. Taking into account the exceptional circumstances, power is also equipped with the exchange of charging system.
Function to select some. With "control" button to select the operating mode surge valve, the controller can control the left valve, right valve or double valve, to achieve full clearance, wide-open, single-valve operation of features such as alternate.
Operation, including the application of controller parameters and control settings to run in two parts. Controlled operation is received after some of the basic input parameters, the operator control procedures, issued a directive by the control center automatically. The operation parameters are as follows: (1) Open the power supply, surge control valve will automatically reset - about the closure of the valve at the same time; (2) select the "control" to determine the work of surge valves, and options are left valve, right valve, double valve; (3) Select "System time" with "hours / minutes / seconds" button to choose the time target, and adjust the system time "+","-"; (4) Select "Start Time "with" hours / minutes / seconds "button to choose the time, using surge irrigation "+","-" adjusted starting time of the incident; (5) Select" water time "with" hours / minutes / seconds " button to choose the time object, identified by a single "+","-" surge irrigation water advance time; (6) select "time interval", the "hours / minutes / seconds" button to choose the time object, use "+", "-" to identify a single time surge irrigation water; (7) select the "surge the number of" surge adjusted by the number of "+","-", every time "+" in the second digital tube plus 1 , the largest to 99, every time "-" in the second tube by a digital 1, the minimum to 0.
After the above settings, the controller to enter the working state automatically. To show that the dual-valve control means "left-open right off" or "right-open left off" the work of the state of the turn, when the "time interval" greater than or equal to "water time", in a cycle at the end, the two valves will be At the same time, the closure of the closing time for the "time interval" minus the "water time", the second round after the work of the state of the cycle; when the "time interval" less than "water time", two-valve can not work at the same time, the circumstances, the only to single valve operation. Any time, once by pressing the "system reset" button, surge valve around the valve will be shut down, thus the termination of the irrigation.
1.3 Control valve and self-controller connections
For ease of use, to avoid illegal or misoperation, surge valve controller and interface standards for the use of industrialization, the connection between the two can use to plug your cable (only can be inserted), simple, safe operation.
2 device performance and characteristics of
Developed surge irrigation equipment has the following properties and characteristics of the work.
Two-valve condition, the single biggest surge over flow valve and the corresponding Q of the irrigated area can be controlled using the following formula to estimate S
Which
Where A cross-sectional area for water pipelines; d is the diameter of pipeline; ε for the discharge coefficient; h for Agricultural Drainage Department at the outlet of pressure head; λ for the coefficient of head loss along the way; ξ for the local head loss coefficient; L for length of pipeline; T for rotation irrigation cycle; m fixed for irrigation; t time daily irrigation; η is coefficient of effective use of water. Schedule is given the assumption that crop rotation irrigation cycle for 7 d, the daily irrigation time of 12 h, different pressure pipeline length and head combinations calculated by the single had the biggest surge valve flow Q and the corresponding control of the irrigated area数质. Irrigation Area on the run, when agricultural drainage outlet at the head of water pressure for Office 30 ~ 50 cm when surge irrigation equipment control area is 4 ~ 6 hm2, in well irrigation area, the control will depend on the size of the surplus pump motor-pumped wells head.
Schedule single had the biggest surge valve to control flow and the corresponding estimates of irrigated area
Head H / m pipeline length L / m
L = 25 m L = 50 m
ε Q/m3.s-1 S/hm2 ε Q/m3.s-1 S/hm2
0.3 0.4 0.030 5 4.61 0.324 4 0.024 7 3.74
0.5 0.4 0.039 4 5.95 0.324 4 0.031 9 4.83
0.8 0.4 0.049 8 7.53 0.324 4 0.040 4 6.11
1.0 0.4 0.055 7 8.41 0.324 4 0.045 1 6.83
1.5 0.4 0.068 2 10.31 0.324 4 0.055 3 8.36
2.0 0.4 0.078 7 11.90 0.324 4 0.063 8 9.65
Note: d = 0.2 m; λ = 0.026; Σξ = 2; m = 750 m3/hm2; η = 0.75.
Since the controller operating voltage 6 V, the average operating current 2.5 A, switching time T = 3 s, battery energy storage to 4 Ah / 6 V. Theoretically, the work of number of 1 920 times, the corresponding surge in terms of the number of double-valve for 480 times on a single valve is 960 times. By the processing equipment, installation limited accuracy, the actual power consumption will be lower the larger the battery the work of a number of charge. Nevertheless, the volume of a charging or operation to meet the irrigation demand for energy gate valve.
The size of solar panels for the 152 mm × 152 mm, the corresponding theoretical power of 1 VA, in the normal light of the average voltage of 8 V, the average charge current is 0.1 A. After the battery fully discharge full time for about 30 h, if the effective charge per day calculated 6 h (10:00 to 16:00), then 5 d. It is suggested that each Director prior to use should be placed outdoors since sunlight charging to ensure the safe operation of a week.
Taking into account the structural design of a multi-valve, and can be used as a single-tube system, but also pay for the replacement of two-pipe system to use the equipment to increase flexibility. Equipment with automatic turn-off water features, can be remote controlled and unmanned.
Controller parameters is simple and involves only the most basic surge irrigation parameters, which will help farmers learn to grasp and easy to promote the use of the field.
Equipment is simple, users will only power cable and surge valve controller can be put into use to connect, and the controller and the speed of the interface box to protect the use of water-proof dust-proof, and suitable farmland in the field of climate and environment conditions.
3, the initial field test
Developed surge irrigation equipment in 1998 was well irrigation and drainage Irrigation District irrigation of winter wheat trials conducted a preliminary field evaluation. Surge intake valve and low pressure hoses used PE aqueduct or agricultural drainage outlet connected at the outlet, and the two surge outlet valve from the hole with the many farm gates hose system. Hole on the brake hose directly into the furrow irrigation water. Experimental design is a single-wide flow of 0.003 m3/sm, furrow length of 150 ~ 200 m, test results show that the work of the whole equipment running well and Surge gate valve to the normal free variable, the accuracy of the flow switching time, the effect of the gate seal better achieve the original design requirements and performance indicators, with a strong practical field.
Assessment results also indicate that the equipment can be very convenient in well irrigation area in the application, on the one hand, the existing low-pressure pipelines can be a convenient outlet and inlet valve surge phase, the surplus on the other hand well pump pressure head for water hose by the PE to provide sufficient power to ensure that a surge into the furrow irrigation methods on the request of discharge. Irrigation Drainage surge valve used will be the two factors. One from the Department of agricultural drainage water head pressure at the outlet of the restriction, when the head must, the water hose and the head loss along the way Surge irrigation equipment produced by their own local head loss will lead to reduced flow into the plot, can not satisfy the wave Chung irrigation requirements of technical parameters. Based on the test results, channel outlet pressure head Department should at least be greater than 30 cm, surge valve pipeline length and it is not too long. The second is the need for the existing agricultural drainage outlet to the appropriate transformation of the structure so that its intake valve surge convergence.
4 Conclusion
Conditions suitable for the development of surge irrigation equipment is to achieve large-scale application of this water-saving irrigation methods, one of the necessary conditions. Has developed a surge of irrigation control valves and automatic valve controller has a multi-purpose, easy to operate features. Preliminary assessment field trial results show that the equipment has reached the design requirements and performance indicators, with a strong practical field. On this basis, will further enhance and improve the control valve and controller since the quality and standards, the use of lightweight materials to replace existing materials, to reduce equipment weight and easy to field mobile and flexible. In addition, the development of surge irrigation equipment and matching the field and the corresponding aqueduct pipe fittings such as gate-hole, thereby providing a good performance, modest prices surge irrigation system complete. Reason to believe that, with the surge irrigation equipment to improve the success of the development and improvement of irrigation system, as well as surge production series surge irrigation technology will be able to water-saving irrigation cause in our country to play its due role.
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